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A Twin-CME Scenario for Ground Level Enhancement Events

Li, G. and Moore, R. and Mewaldt, R. A. and Zhao, L. and Labrador, A. W. (2012) A Twin-CME Scenario for Ground Level Enhancement Events. Space Science Reviews, 171 (1-4). pp. 141-160. ISSN 0038-6308. http://resolver.caltech.edu/CaltechAUTHORS:20121101-104526076

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Abstract

Ground Level Enhancement (GLEs) events are extreme Solar Energetic Particle (SEP) events. Protons in these events often reach ∼GeV/nucleon. Understanding the underlying particle acceleration mechanism in these events is a major goal for Space Weather studies. In Solar Cycle 23, a total of 16 GLEs have been identified. Most of them have preceding CMEs and in-situ energetic particle observations show some of them are enhanced in ICME or flare-like material. Motivated by this observation, we discuss here a scenario in which two CMEs erupt in sequence during a short period of time from the same Active Region (AR) with a pseudo-streamer-like pre-eruption magnetic field configuration. The first CME is narrower and slower and the second CME is wider and faster. We show that the magnetic field configuration in our proposed scenario can lead to magnetic reconnection between the open and closed field lines that drape and enclose the first CME and its driven shock. The combined effect of the presence of the first shock and the existence of the open close reconnection is that when the second CME erupts and drives a second shock, one finds both an excess of seed population and an enhanced turbulence level at the front of the second shock than the case of a single CME-driven shock. Therefore, a more efficient particle acceleration will occur. The implications of our proposed scenario are discussed.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1007/s11214-011-9823-7DOIArticle
http://www.springerlink.com/content/r03791283644j701/PublisherArticle
http://rdcu.be/tchmPublisherFree ReadCube access
Additional Information:© 2011 Springer Science+Business Media B.V. Received: 31 January 2011; Accepted: 8 August 2011; Published online: 17 January 2012. This work is supported in part by NSF ATM-0847719 (CAREER), NASA NNX07AL52A (EpSCoR) and an ORAU Ralph E. Power Junior Faculty Enhancement Award for GL at UAHuntsville. The work at Caltech was supported by NASA grants under grants NNX8AI11G and NNX06AC21G. The authors thank Dr. Nat Gopalswamy and Dr. Nariaki Nitta for organizing the two GLE workshops where this work was largely completed.
Group:Space Radiation Laboratory
Funders:
Funding AgencyGrant Number
NSFATM-0847719
NASANNX07AL52A
ORAU Ralph E. Power Junior Faculty Enhancement AwardUNSPECIFIED
NASANNX8AI11G
NASANNX06AC21G
Subject Keywords:Solar energetic particles; Ground level enhancement events; Diffusive shock acceleration
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2012-14
Record Number:CaltechAUTHORS:20121101-104526076
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20121101-104526076
Official Citation:Li, G., R. Moore, et al. (2012). "A Twin-CME Scenario for Ground Level Enhancement Events." Space Science Reviews 171(1): 141-160.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:35240
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:06 Nov 2012 19:25
Last Modified:05 Jun 2017 14:32

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